Field
The present disclosure relates to a foldable display device.
Description of the Related Art
An image display device which implements various information on a screen is a core technology in an information communication era and is developing to be thinner, lighter, more portable, and has higher performance. Thus, an organic light emitting display device which controls an amount of emitted light of an organic light emitting element to display images is getting the spotlight.
The organic light emitting element is a self-emitting device using a thin light emitting layer between electrodes so that it can be manufactured to be thin. The normal organic light emitting display device has a structure in which a pixel driving circuit and an organic light emitting element are formed on a substrate and light emitted from the organic light emitting element passes through a substrate or a barrier layer to display images.
Since the organic light emitting display device is implemented without having a separate light source device, the organic light emitting display device may be easily implemented as a flexible, bendable, and foldable display device. In this case, a flexible material such as plastic or a metal foil is used for a substrate of the organic light emitting display device. Further, in the flexible and foldable display device, generally, a plurality of thin film layers is laminated on a substrate.
For example, the foldable display device may be configured by several functional films and a series of adhesive layers for lamination of the functional films. The foldable display device needs to be quickly restored to be flat in its original state after being folded and then unfolded. However, materials which are currently used have a limitation in complete restoration and such restoration characteristic is lowered under a high temperature or high humidity environment. Thus, in order to improve usability of the foldable display device, material and/or structural improvements for ensuring flexibility and restoration characteristic are demanded.